Scan Channels

XBee & XBee Gateway XBee - Zigbee
1

Hi all,
I’m new in the xbee world, and i have a question.
I want to set Scan Channels and i understand how but i can’t understand how write the value.

Example:

I read in the manual that:

if the operating
channel is 0x0B, set SC to
0x0001. If the operating channel
is 0x17, set SC to 0x1000.

but I can not understand how calculate the number from 0x17 to 0x1000

or calculate range that i want…

For example, setting SC to 0x281 enables
scanning on channels 0x0B, 0x12, and 0x14, in that order.

Can you help me?

2

Why do you want to set this? Are you trying to force use of a single channel? This risks picking a useless channel.

Normally, you leave the SC=0x1FFE in all devices and let the coordinator try to find a clear, usage channel. The other devices ‘scan’ through all enabled channels to find a coordinator.

3

Why do you want to set this? Are you trying to force use of a single channel? This risks picking a useless channel.

Normally, you leave the SC=0x1FFE in all devices and let the coordinator try to find a clear, usage channel. The other devices ‘scan’ through all enabled channels to find a coordinator.

thanks for the answer but i need to set the channel or the range channel…

4

Okay, understand that there are 2 weird things here.

First, Zigbee channels are numbered 11 to 26. Why? Are they planning to steal channels 0-10 from lower spectrum some day? heck if I know.

Second, these are often given as hex, as 0x0B to 0x1A. Digi docs sometimes are a bit cavaler and just talk about channel 0D without including the 0x.

So when you mention “17” - make sure you understand if you want 17 (so 0x11) or 23 (so 0x17)

Do a Google search of ‘Zigbee channels’ and you’ll find lots of nice graphs and details.

So >MY UNDERSTANDING< (which may be wrong) is that 0x281 would be channels 11, 18 and 20 (0x0B, 0x12 and 0x14). So the first channel (11 or 0xB) is 0x0001.

5

Ok, but i can’t understand the mechanism to translate the sequence of channel (11,18,20) to hex number 0x281 or sigle channel 0xB to 0x0001. For example if i want set the sequence 12,13,16 how can calculate the corrisponding number?

6

You are thinking too hard :slight_smile: Just write it down on paper (or Excel if you are fancy)

11 (0x0B) = 0x0001
12 (0x0C) = 0x0002
13 (0x0D) = 0x0004
14 (0x0E) = 0x0008
15 (0x0F) = 0x0010
16 (0x10) = 0x0020
17 (0x11) = 0x0040
18 (0x12) = 0x0080
19 (0x13) = 0x0100
20 (0x14) = 0x0200
21 (0x15) = 0x0400
22 (0x16) = 0x0800
23 (0x17) = 0x1000
24 (0x18) = 0x2000
25 (0x19) = 0x4000
26 (0x1A) = 0x8000

7

Thanks alot… :slight_smile: then if i want a set of channels should i sum the respective value?

8

Yes - technically you ‘OR’ them together, but adding/summing should work as well.

I created a wiki page for you: http://www.digi.com/wiki/developer/index.php/Channels%2C_Zigbee

So if you want the four channels which do not overlap the standard 3 WiFi bands, you’d want ZB channels 15, 16, 21, and 22. So you would set the coordinator’s scan_channel/SC to 0x0C30.

Generally, leave all other nodes with the default SC. They will waste a small amount of time during the original association, but it allows you to change your mind more easily in the future & only change one SC value.

9

Thanks alot for all… You helped me alot!!! :slight_smile:

10

Hello guys.

I’m trying to scan just one channel. II’m using waspmote v1.1 and xbee 802.15.4 S1.

I tried using the example http://www.libelium.com/development/waspmote/examples/802-07-energy-scan/#

But appears the following error:

C:\Users\Diegui\Desktop\Papeo\Ramos\Teoría de Información y Código\Software\waspmote-ide-v.01-windows\hardware\cores\wasp_v018/WaspXBeeCore.h:1621: error: ‘Sd2Card’ does not name a type

In function ‘void setup()’:
In function ‘void printEnergyChannel()’:
Bad error line: -4

What does this mean ? Please any help